What Is Spaghetti Code?

Definition

Spaghetti code is code that is difficult to understand and eventually maintain because its structure is all over the place hence the word spaghetti in its name.

Use cases and Examples

One reference used in most examples is the Goto statement.

Usually, code is meant to be executed from the top to bottom, but keywords such as Goto allow the execution to be moved to a previous line or a line entirely in a different file somewhere.

This makes it difficult to follow the execution path.


01: $x=(int)readline("enter a number");
02: if ($x%2==0)
03:    goto abc;
04: echo "x is an odd number";
05: return;
06: abc:
07: echo "x is an even number";

Most developers avoid the use of the Goto even if the programming language in use supports it. However, there are still many ways to end up with spaghetti codebase. Eg: By not organizing source code files properly or in some situations mixing up different programming languages in a messy way eg: mixing up HTML with PHP.


01: $results = array(1, 2, 3, 4, 5, 6);
02: $max = count($results);
03: for($i = 0; $i < $max; $i++) {
04:     echo "<li>";
05:     echo "<div>result " . $results[$i] . "</div>";
06:     $i++;
07:     echo "<div>result " . $results[$i] . "</div>";
08:     echo "</li>";
09: }

Summary

Most developers start projects without knowing it will end up as spaghetti code, it usually happens over time, hence developers need to learn patterns to follow when writing code, these are referred to as software patterns and sometimes going against them is known as an anti-pattern.

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